As a follow up to some questions received, the following is the email response from Sonya Carlson of NHDES.
Hi Dusty,
The link from our website is: http://des.nh.gov/organization/divisions/water/wmb/beaches/samples.htm
The Center For Disease Control information is http://www.cdc.gov/healthywater/swimming/
There is no reason to think that the entire lake is contaminated. While there is no way to be sure without testing every single location in a lake, the beach is the most likely place for bacteria to be.
The dogs are usually not effected by this type of bacteria.
It is only a problem if you drink the water. Canoeing or kayaking is fine.
Sonya Carlson, NHDES Beach Program Coordinator